Dye intermediate



Patented Mar. 28, 1944 'UNITED STATES PATENT OFFICE.

2,345,093 DYE INTERMEDIATE d William Waldo Williams,

Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of Leslie G. S. Brooker an New Jersey N Drawing. Application August 21, 1940, Serial No. 353,501

14 Claims.

While the corresponding aryl quaternary salts.

are wholly unavailable.

The cyclammonium alkyl quaternary salts containing an alkylmercapto group in a reactive position can be prepared by treating a heterocyclic nitrogen base containing an alkylmercapto group with an alkyl salt. However, aryl quaternary salts cannot be prepared by treating a heterooyclic nitrogen base containing an alkylmercapto group, with an aryl salt. Certain cyclammonium alkyl' quaternary salt containing an alkyhnercapto group can be prepared by treating a cyclammonium alkyl quaternary salt containing a halogen atom, with a mercaptan. However, cyclammonium aryl quaternary salts containing a halogen atom in a reactive position are unknown, so that it has not been possible to attempt to react the aryl quaternary salts with mercaptans. It is known that N -alkylthioquinolones and N-alkylthiobenzothiazolones can be treated with alkyl salts to give substances which have been portrayed as sulfonium compounds (see British Patent 423,792, accepted February -7, 1935), but which may actually be cyclammonium alkyl quaternary salts containing an alkylmercapto group.

We have now found that cyclammonium arylquaternary salts containing an-alkylmercapto group in a reactive position-can be prepared by treating a compound such as a N-arylthio-' benzothiazolone, i. e. a N-aryl heterocyclie nitrogen base containing, in'a reactive position,

a doubly bound sulfur atom, with an alkyl salt;

Moreover, we have found that -'new cyanine and new merocyanine dyes can be prepared from It is, accordingly, an object of curinvention such substances.

to provide cyclammonium aryl quaternary'salts containing an alkylmercapto group in a reactive position. A further objectis to provide a process for preparing such aryl quaternary salts. A still further object is to provide new dyes prepared from such aryl quaternary salts and a process for preparing such dyes. Other objects will become apparent hereinafter.

In accordance with our invention, we treat a compound such as a N-arylthiobenzothiazolone with an alkyl salt. As alkyl salts, alkyltoluenesulfonates are advantageously employed. Alkyl iodides and dialkyl sulfates can also be .em-v ployed. The alkyl salt .is advantageously em- In this manner the quaternary salt was obtained,

ployed in excess; from one and one-half to two and one-half molecular proportions for each molecular proportion of N-arylthiobenzothiazolone being preferable. Heat accelerates the formation of the 'benzothiazolium salts. The following example will serve to illustrate the formation of our new benzothiazolium salts.

EXAMPLE 1. Z-methylmercaflto-i-phenylbenzothiazolium p-toluenesulfonate Cg Hj \S OsCaHr CHa 12.2 g. (1 mol) of B-phenyl-Z-thiobenzothiazolone and 14.0 g. (1 mol+50% excess) of methylp-toluenesulfonate were heated together upon a steam bath for about 4 hours. The reaction mixture was cooled, washed with two 100 cc. portions of diethyl ether, triturated with .50 of acetone, the acetone mixture chilled and the quaternary salt filtered off and dried in the air.

in yield, as colorless crystals, melting at 176 to 177 C. The p-toluenesulfonate can be'converted to the iodide or the perchlorate by treating an aqueous solution thereof with an aqueous solution of a water-soluble metal iodide or perchlorate. l 1

In a similar manner, 2-ethylmercapto-3-phenylbenzothianzolium p-toluenesulionate, as well as 2 methylmercapto 3 naphthylbenzothiazolium-p-toluenesulfonate can be prepared.

The 3-phenyl-2-thiobenzothiazolone employed in the above example as well as similar N-aryl compounds can be prepared by treating the corresponding oxo compound (in this specific case 3-phenyl-2-benzothiazolone) with phosphorous pentasulfide in xylene as described in our copending application Serial No. 353,500, filed of even date herewith (now U. S. Patent 2,330,203, dated September 28, 1943).

Our new .benzothiazolium aryl quaternary salts can be condensed with malonic acid in the presence of pyridine to give N -aryl thiacyanines, as illustrated in the following example.

EXAMPLE 2.- 3,3--diphenylthiacyanine iodide was heated on a steam bath for 45 minutes. The hot reaction'mixture was poured into 20 cc. of aqueous sodium-iodide solution containing 1.5 g. (1 mol.+100% excess) of sodium iodide. The resulting mixture was cooled and diluted with 25 cc. of diethyl ether, whereupon the thiacya- 7 nine iodide precipitated. It was filtered oif,"

EXAMPLE 3.1 -ethyl-3-phenyZthia-2 -cyanine iodide 1.2 g. (1 mol.) of 3-phenyl-2-thiobenzothiazolone and 0.95 g. (1 mol.) of methyl-p-toluenesulfonate were heated together upon a steam bath for two hours. To the resulting mass were added 1.5 g.- (1 mol.) of quinaldine ethiodide, 10 cc. of absolute ethyl alcohol and 0.5 g. (1 mol.)-of triethylamine. The resulting mixture was refluxed gently for 3 minutes, cooled and-the dye filtered off. 1.4 g. (56% yield) ofcrude dye was thus obtained. The dye was dissolved in absolute ethyl alcohol and the solution decolorized with Norite. After a further recrystallization from absolute ethyl al-- cohol (50 cc. per gram of dye), the dye was btained, in-14% yield, as orange colored needles,

melting at 241 to 242 0. with decomposition. 45

The dye sensitized a photographic gelatino-silver-bromiodide emulsion to 560 mu with a maximum at 520 mu.

"Emmi-s 4. 1' thyz-s-phehyztht -reyantite i d d v CtHs 1.2 g. (1 mol.) of 3-phenyl-2-thiobenzothiazolone and 0.95 g. (1 mol.)of-methyl-p-toluenesulfonate were heated together on a steam bath for four hours. -Tothe resulting mass were'added 1.5 g. (1 mol.) of lepidine ethiodide, 10 cc. of absolute ethyl alcohol and 0.5 g. (1 mol.) of tri- CzHs ethylamine. The resultingmixture was refluxed 65 for 10 minutes, cooled, diluted with an equal volume of diethyl ether and allowed to stand overnight. Theether layer was decanted and the oily residue was dissolved in 15 cc. of absolute ethyl alcohol, the alcoholic solution chilled and the crude dye filtered off and dried in the air. In this manner, 1.0 g. (40% yield) of dye was obtained. After three recrystallizations from absolute ethyl alcohol (15 cc. per gram of dye), the

dye was obtained, in' 18% yield, as glistening red-- crystals melting at 277 to 279 C. with decomposition. The dye sensitized a photographic silver bromiodide emulsion to 570 mu with a maximum at about 530 mu.

EXAMPLE 5.--3-ethyl-3'-phenylthiacyanine iodide 1.2 g. (1 mol.) of 3-phenyl-2-thiobenzothiazolone and 0.95 g. (1 mol.) of methyl-p-toluenesulfonate were heated together on a steam bathfor two hours. 1.5 g. .(1 mol.) of 2-methylbenzothiazole ethiodide, cc. of. absolute ethyl alcohol and 0.5 g. (1 mol.) of triethylamine were added to the reaction mixture, and the resulting mixture was refluxed for five minutes, cooled and the dye filtered off. In this manner, 1.2 g. (48% yield). of crude dye was obtained. After two recrystallizations from absolute ethyl alcohol (50 cc. per gram of dye) the dye was obtained, in 32% yield, as yellow crystals, melting at 265 to 266 C. The dye sensitized a photographic gelatino-silver-chloride emulsion to 485 mu with a maximum at 460 mu. I

In Examples 3, 4 and 5, where triethylamine is employed as acid-binding agent, other strong organic bases can be used, especially tertiary strong organic bases, such as Nmethyl-piperidine, triethanolamine, etc. Still other acid-binding agents, such as sodium or potassium carbonate are very satisfactory. Heat accelerates the for.- mation of the dyes.

In the preparation of photographic emulsions containing our new dyes, it is only necessary to disperse the dyes in the emulsions. The methods of incorporating dyes in emulsions are simple and well known to those skilled in the art. It is convenient to add the dyes from solutions inappropriate solvents. Methanol has proven satisfactory as a solvent for our new dyes. Ethyl alcohol or acetone may also be employed where the solubility of the dyes in methanol is lower than desired. 7

Sensitization by means of our new dyes is, of course, directed primarily to the ordinarily employed gelatino-silver halide developing out emulsions. The dyes are advantageously incorporated in the washed, finished emulsions and should, of course, be uniformly distributed 55 throughout the emulsions. j

The concentration of our new dyes in the emu1-- sion can vary widely, i. e. from about 5 to about 100 mgs. per liter of flowable emulsion. ,The concentration of the dye will vary according to the type of light-sensitive material in the, emulsion and according to the efiects desired. The suitable and most economical concentration for any given emulsion will be apparent to; those skilled in the art upon making the ordinary tests and observations customarily used in the art of emulsion making. j

To prepare a gelatino-silver-halide emulsion sensitized with one of our new dyes, the following procedure is satisfactory: A quantity of the so .dye is dissolved in methyl alcohol or other suitable solvent and a volume of this solution (which may be diluted with water) containing from 5 to 100 mgs. of dye is slowly added to about 1000 cc. of a gelatino-silver-halide emulsion, with 75 stirring. Stirring is continued until the dye isuniformly distributed throughout the emulsion. With most of our new dyes, to mgs. of dye per liter of emulsion suffices to produce the maximum sensitizing efiect with the ordinary gelatino-silver-bromide (including bromiodide) emulsions. With fine-grain emulsions, which includes most of the ordinarily employed gelatin'osilver chloride emulsions, somewhat larger concentrations of dye may be necessary to secure the optimum sensitizing effect.

The above statements are only illustrative and are not to be understood as limiting our invention in any sense, as it will be apparent that our new dyes can be incorporated by other methods in many of the photographic silver halide emulsions customarily employed in the art. For instance, the dyes may be incorporated by bathing a plate or film upon which an emulsion has been coated, in the solution of the dye, in an appropriate solvent. Bathing methods, however, are not to be preferred ordinarily.

What we claim as our invention and desire to be secured by Letters Patent of the United States is:

l. A process for preparing a benzothiazolium aryl quaternary salt comprising treating a N- aryl-2-thiobenzothiazolone with an alkyl-ptoluenesulfonate.

2. A process for preparing a benzothiazolium aryl quaternary salt comprising treating one molecular proportion of N-aryl-2-thiobenzothiazolone with from one and one-half to two and one-half molecular proportions of an alkyl salt.

3. A process for preparing a benzothiazolium aryl quaternary salt comprising treating one molecular proportion of N-ary1-2-thiobenzothiazolone with from one and one-half to two and one-half molecular proportions of an alkylp-toluenesulfonate.

4. A process for preparing a benzothiazolium phenyl quaternary salt comprising treating a N-phenyl-Z-thiobenzothiazolone with; an alkyl salt.

5. A process for preparing a benzothiazolium phenyl quaternary salt comprising treating a N-phenyl-2-thiobenzothiazolone with an alkylp-toluenesulfonate.

6. A process for preparing a benzothiazolium phenyl quaternary salt comprising treating one molecular proportion of a N-phenyl-Z-thiobenzothiazolone with from about one and one-half to about two and one-half molecular proportions of an alkyl salt.

'7. A process for preparing a benzothiazolium phenyl quaternary salt comprising treating one molecular proportion of a N-phenyl-Z-thiobenzothiazolone with from about one and one-half to about two and one-half molecular proportions of an alkyl-p-toluenesulfonate.

8. A process for preparing a benzothiazolium phenyl quaternary salt comprising treating a N phenyl-Z-thiobenzothiazolone with methyl-ptoluene-sulfonate.

9. A process for preparing a benzothiazolium phenyl quaternary salt comprising treating one molecular proportion of a N-phenyl-z-thiobenzothiazolone with from one and one-half to two and one-half molecular proportions of methylp-toluenesulfonate.

10. A benzothiazolium aryl quaternary salt containing an alkylmercapto group in the 2- position. w

11. A benzothiazolium aryl quaternary salt containing a methylmercapto group in the 2- position.

12. A benzothiazolium phenyl quaternary salt containing an alkylmercapto group in the 2- position.

13. A benzothiazolium phenyl quaternary salt containing a methylmercapto group in the 2- position.

14. A benzothiazolium the following formula:

quaternary salt having N C5115 SOa.CeH4.CHa 

